Hyperinflammation in patients with chronic granulomatous disease leads to impairment of hematopoietic stem cell functions.

Background: Defects in phagocytic nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) function cause chronic granulomatous disease (CGD), a primary immunodeficiency characterized by dysfunctional microbicidal activity and chronic inflammation.
Objective: We sought to study the effect of chronic inflammation on the hematopoietic compartment in patients and mice with X-linked chronic granulomatous disease (X-CGD).
Methods: We used immunostaining and functional analyses to study the hematopoietic compartment in patients with CGD.
Results: An analysis of bone marrow cells from patients and mice with X-CGD revealed a dysregulated hematopoiesis characterized by increased numbers of hematopoietic progenitor cells (HPCs) at the expense of repopulating hematopoietic stem cells (HSCs). In patients with X-CGD, there was a clear reduction in the proportion of HSCs in bone marrow and peripheral blood, and they were also more rapidly exhausted after in vitro culture. In mice with X-CGD, increased cycling of HSCs, expansion of HPCs, and impaired long-term engraftment capacity were found to be associated with high concentrations of proinflammatory cytokines, including IL-1β. Treatment of wild-type mice with IL-1β induced enhanced cell-cycle entry of HSCs, expansion of HPCs, and defects in long-term engraftment, mimicking the effects observed in mice with X-CGD. Inhibition of cytokine signaling in mice with X-CGD reduced HPC numbers but had only minor effects on the repopulating ability of HSCs.
Conclusions: Persistent chronic inflammation in patients with CGD is associated with hematopoietic proliferative stress, leading to a decrease in the functional activity of HSCs. Our observations have clinical implications for the development of successful autologous cell therapy approaches.
(Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)